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SB Fourteen stalls under load

Glenn Brooks

Aluminum
Joined
Nov 16, 2014
Location
Woodinville, Wa
Just bought a new to me a 220v 3P SB Fourteen with Reeve drive for variable speed control. Nice, tight machine, but after a few test cuts, discovered it stalls whilst taking a .060" cut on mild steel shafting. Spindle slowed down to around 50 RPM due to tool pressure in the work.

Iam going to open it up today and look under the hood.

Any ideas what went wrong here?

Thanks
Glenn
 
Just bought a new to me a 220v 3P SB Fourteen with Reeve drive for variable speed control. Nice, tight machine, but after a few test cuts, discovered it stalls whilst taking a .060" cut on mild steel shafting. Spindle slowed down to around 50 RPM due to tool pressure in the work.

Iam going to open it up today and look under the hood.

Any ideas what went wrong here?

Thanks
Glenn

I'd start by checking the belts
 
This lathe is convenient for tapping as the spindle can be reversed at any speed. There is a component of the variable drive that is a specialized type of collet with two keyways 180 degrees out. The keyway has a sharp corner at the root and may eventually crack near the bore end of the collet.
The shop had one where the front panel could be removed to access the variable drive components. If the the variable disc is not tight on the belt the collet may be damaged or the collet assembly is not properly tightened.
John
 
At first thought maybe it is hooked up to 220 but wired for 440, or it is losing a leg on the motor. But I am not familiar with this machine, so I defer to others that know more than I do.

Best of luck,

Marc
 
Thanks guys, well troubleshooting this morning, the spindle ground to a halt again and the motor wouldn't restart. Just emits a very loud buzzing sound - more like a loud 'Bbratttttttttte'. Tried to spin the spindle, but heard and felt a loud clunking noise over the Buzzing sound coming out of the motor. Funny thing is, the pully and spindle system all turns easily by hand.

So will pull the motor and see what's going on.

Any suggestions about parts or transmission drawings?

PS. I don't think this is actually a Reeves gear. I suspect it is a SB offshore copy of the reeve idea and design. The principle component seems to be the transmission that drives the headstock.

Thanks
Glenn
 
Thanks guys, well troubleshooting this morning, the spindle ground to a halt again and the motor wouldn't restart. Just emits a very loud buzzing sound - more like a loud 'Bbratttttttttte'. Tried to spin the spindle, but heard and felt a loud clunking noise over the Buzzing sound coming out of the motor. Funny thing is, the pully and spindle system all turns easily by hand.

So will pull the motor and see what's going on.

Any suggestions about parts or transmission drawings?

PS. I don't think this is actually a Reeves gear. I suspect it is a SB offshore copy of the reeve idea and design. The principle component seems to be the transmission that drives the headstock.

Thanks
Glenn

The FOURTEEN was made in the USA
email replied to.
Ted
 
Belts were tight. Pulled the drive assembly from the cabinet. Motor and transmission power up and turn freely with no load. Pulled the top cover off the tranny. Everything seems fre and not worn. No bits of gear clogging anything. However the oil was extremely saturated with metal filings from long term wear. Top end-spindle, pulley, bearings and belts all turn freely, with no noise.

So, Something must be wrong in the motor. Dropped one phase maybe??
 
Hum and no spin on a 3 phase motor sounds like a dropped phase. Contactor/starter problems perhaps if you know the power in is good. With some luck it has an overload on there to cut the power before the motor melts. They will do that if powered with a missing leg, and it doesn't take long.
 
Also a mention, once its spinning you can drop a phase and have the motor continue to run. It makes something like half power though, which could explain the stall.
 
Nice, tight machine, but after a few test cuts, discovered it stalls whilst taking a .060" cut on mild steel shafting.
0.06" depth of cut doesn’t mean anything. You’d have to add the feed rate, then one would know something about energy conversion, forces, and speeds.
 
Finally figured out what's going on. After removing all the dust covers and safety shields, iand stripping the drive system out of the lathe bed, t was obvious that the reeves drive belt was slipping on the lower (driven) pully that mounts on the motor shaft. So as the belt slipped under the deeper cut, it stalled the spindle, stopping the work from turning.

The motor continued to spin for a few seconds, until the slack belt finally pinched And jammed on the lower shift/driven pulley, overheating the motor and initially stopping the motor.

Still no idea why the motor dropped phase and started making the horrendous racket, except for possibly thermal fault of some kind.

Fortunately no damage to the motor and all parts of the system check,out fine re: resistance and voltage.

Finding a replacement belt locally is impossible. Apparently the West coast has no industrial capacity or supply chain left anymore. But that's another story!

Glenn
 
Finding a replacement belt locally is impossible. Apparently the West coast has no industrial capacity or supply chain left anymore. But that's another story!

Glenn

I found Reeves belts still listed by .. pretty sure it was Gates.

One seriously costly booger for my 5 HP mill.

Then looked under FSN/NSN, and sure enough some sort of ride-on industrial scrubber the Gummint used for stupid-pill warehouse floor maintenance used the same belt. Then found a NOS one at half the new price in a Gulf coast warehouse of a remainderman/salvager. Again via the FSN/NSN logistics system, AND NOT ebay or such.

Downside? It was unused. But had also taken one Hellacious 'set' into the oval shape of the packaging.

You might try that channel and find yerself a Reeves belt that also once fit a Strategic Army Command Airmobile dirty-socks washer or such.

Bill
 
Hi Bill,

I followed a similar methodology to yours and looked at NOS on eBay and Amazon. Ordered one, I HOPE, is in decent condition.

FWIW: l learned these belts have two points of failure. 1)they wear, stretch, and loose tension, hence slip. 2) they get hard over time and develop a 'set' such as you mentioned. This set, according to a Gates rep, inhibits the belts from gripping properly in the variable speed pulleys - hence they slip.

So,I opted for a 'new' belt in original packaging from a current manufacturer, but sold through a clearance warehouse guy of some sort, in hopes I will get something usable...

Variable speed drive systems seem to be still around, but seem not well documemted. Almost like a black art.

Glenn
 
This is very topical for me.
Trying to source a Lewllen/Reeves belt for my Diehl Lumber jointer.
Factory said they had to charge around $1,800 for the last one, "many" years ago; no further sources. But tech was very helpful, made similar suggestions to the ones from PM'rs above.

I found this code/cross reference online digging around.
Might help someone.

https://www.timkenstore.ca/images/Baldor/pdf/pt9_12.pdf


I'm hoping to cross reference mine (1-13/16" W 26° x 50" long more or less. There is some adjustment on the machine besides the pulleys. The current 52.2" long belt appears to have always been too long. It has worked in the past, but always slipped with thick/heavy boards going through.

FWIW, I ordered mine for the Diehl from these guys

2926V486 GATES OEM Equivalent Variable Speed Belt – V-Belt Guys

Good help over the phone, will see when it arrives end of week.

smt

PS - discovered it even cheaper elsewhere. But OK with that, at least one is on its way! Point being, keep digging.
 
Last edited:
Stephen, Exactly! Keep digging. Looks like you got a decent price.

BTW, the Gates rep advised industrial settings still use these reeves drive style units a lot. The belts require routine tensioning, often involving laser measuring devices to set the required 8 pounds of tension - which is not very much tension. But it is critical to keep them from slipping.

Also, the most common cause of belt failure is .... Overtensioning. To tight, they break.

If you still have trouble with your new belt slipping. Try shimming the drive unit to raise it up higher than the adjustment allows.
 
PS - discovered it even cheaper elsewhere. But OK with that, at least one is on its way! Point being, keep digging.

As I do not expect them to ever get more readily available, nor less-costly, I considered a second one I found as a spare.

OTOH, the old belt had not failed in many, many years, nor looked to be all that badly worn. Discovered later that the seller had replaced it, then not used the mill much afterwards.

Mea Culpa, I had over-hastily razored a rather good belt in half to get the Quartet mill apart faster, as Adam was already giving up part of his weekend in the midst of a record-setting Pensacola flood.

If your operation is more dependent on the system it serves than mine, a spare could be cheap insurance.

Bill
 








 
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